Well, you already know it's not Jelly Bean, but T-Mo is sending an OTA update to the Galaxy S III right now. It's a minor one, mostly dealing with some Touchwiz stuff you likely don't use, as well as a behind-the-scenes tweak to pinch and zoom. Woo.

Current Version - Android version 4.0.4/Software version T999UVLJ4

Version:

Android version 4.0.4/Software version T999UVLJ4

Approved 10/17/2012

Improvements:

Resolved Media Hub playback issues

Pinch & Zoom backend changes – No visible user changes

Prerequisites

OTA and Samsung Kies update

T999UVLH2, T999UVLG1 or T999UVLEM

Device software is not rooted

50% battery life

Data connection

50 MB available memory (File size of update is 12 MB)

The 12MB update is available via OTA right now, but if you'd rather use Kies for some weird reason, you'll have to wait until tomorrow.